Toshiba PF tri-sync high pitched whining noise 15kHz

[PascalP]

So the chassis in my New Net City is making an audible high pitched whining noise on 15kHz content.
Did notice it already for some time and initially tought it was a squealing fan in my PSU or something, but I now figured out after swapping some PCB’s it only occurs with 15kHz.
On 31kHz it is dead silent.

Any suggestions where to start? Or just pull the chassis and start with a cap kit?

 

[BuddyC]

A full recap helped with my old NNC’s, but was louder with the PD2367 chassis. Had a feeling it didn’t like 15khz material at all… Most of the whining came from the yoke.

 

[_C4m]

Firstly I would pull over the monitor from the cabinet.

Then I'd grab a pencil or any stick of non conductive material. With the monitor on , apply pressure in the plastic ring surronding the yoke. If the whining change pitch or completely dissapear, is most likely you have to dissassambley the yoke and give it a thorough clean. Sometimes pieces of magnets or convergence strips go to die there causing vibration and hence the whining.

If that doesn´t give you results, repeat the operation with the different coils from the chassis itself. Again, if by applying pressure the whining stop or change pitch you found the guilty. Just swap the coil or isolate it somehow (liquid tape, silicone...)

If that doesn´t give you results... maybe the whining come from the flyback coils. Then you are a bit screwed. I wouldn't change a flyback just because of this, I'd just learn to live with it.

I hope you manage to fix your problem!